In reply to Will Hansen.

In March 1845, a copy of this octavo edition of Magna Charta (1587) sold at the auction of B. H. Bright's collection. A source from 1861 indicates that the copy was printed on "large paper" and has "MS. notes." Unfortunately, I cannot easily examine a copy Bright auction catalog to see precisely what it says about this book. I don't know the lot number, but a description should appear in Catalogue of the Valuable Library of the Late Benjamin Heywood Bright, Esq.(1845). I wouldn't be too dreadfully surprised if it is in fact the very copy Duke now has, but it is just as likely (if not more likely) to be another.

I'd want to know what the dimensions of the Bright copy are, because I have come across what get described as "large" or "large paper" octavos. These books sometimes have text blocks of a typical size, but with pretty large margins—though nothing like what we are seeing here.

For a similar book: the Beinecke Library has a copy of Littleton's Tenures in 12mo that been laid into larger paper, creating a mise-en-page that's almost identical to what we see in this Magna Charta. It is also interleaved with blanks: http://brbl-dl.library.yale.edu/vufind/Record/3447270?image_id=1409933. The big difference of course is that this one was not printed on larger paper, as this 1587 Magna Charta appears to be.